Split-sustainer operation for gaseous discharge display panels

ABSTRACT

There is disclosed an improved sustainer supply system that allows more economical addressing techniques for gaseous discharge display panels. There is particularly disclosed a sustainer supply system wherein the panel discharge currents need not be carried by the addressing drive circuitry. According to the invention each panel electrode or conductor line is addressable by a resistor-diode addressing matrix. The invention provides an addressable sink circuit which sinks current from any diode resistor combination.

United States Patent [1 1 Trogdon SPLIT-SUSTAINER OPERATION FOR GASEOUS DISCHARGE DISPLAY PANELS Feb. 12 1974 Primary Examinen-Roy Lake Assistant Examiner-Lawrence J. Dahl Attorney, Agent, or Firm-Jim Zegeer; Donald Keith [75] Inventor. Ray L. Trogdon, Perrysburg, Ohio wedding; E. l Holler [73] Assignee: Owens-Illinois, Inc., Toledo, Ohio 221 Filed: June 7, 1972 [57] ABSTRACT There is disclosed an improved sustainer supply sys- [Zl Appl' 260687 tem that allows more economical addressing techniques for gaseous discharge display panels. There is [52] US. Cl. 315/169 TV, 315/169 R particularly disclosed a sustainer supply system [5] Int. Cl. H05b 37/00 wherein the panel discharge currents need not be car- [58] Field of Search 315/169 R, 169 TV ried by the addressing drive circuitry. According to v the invention each panel electrode or conductor line is [56] References Cited addressable by a resistor-diode addressing matrix. The UNITED STATES PATENTS invention provides an addressable sink circuit which 3,665,400 5 1972 Leuck 315/169 R x Smks current fmm any dwde 6 Claims, 2 Drawing Figures E ERA E 50 SUSTAIN WRIT s SUPPI. 1 SOURCE L 595 ADDRESSABLE uP-susrA/N RESISTOR SOURCE DRIVE/2 5 omvzs "n ADJACENT LOGIC i RES'STORS FROM CONTROL INPUT 8 INPUTS To a/ 40 53% 1/22 [240ml Esme) Dggglsgm AND SUSTA/NER TRANSISTORS 0,61 Q FROM 0.477: a colvriaot a T 25(1)) fs i' fiz zs asav 50 LOGIC m PUT V0 ADDHESSABLE 4g SINK CIRCUIT DOWN SUS TA/N SOURCE PATENTED FEB I 2W4 SHEET 1 [IF 2 C 01. UMN ADDRESS AND S US TA /N ROW ADDRESS AND SUSTAIN I Q 0 Z r L "Wm WD D N A w m U S 5 W V R FIG. 1

SPLIT-SUST AINER OPERATION FOR GASEOUS DISCHARGE DISPLAY PANELS The present invention is directed to split-sustainer systems for operating gaseous discharge display panels and provides improved and more economical operation for such panels. Such panels are disclosed in Baker, et al., U.S. Pat. No. 3,499,167 and Bitzer, et al., U.S. Pat. No. 3,559,199. In the Baker, et al. patent, such a panel is constituted by a pair of glass plate members joined in spaced apart relation by a spacer sealant member. The glass plate members carry dielectrically coated multiple conductor arrays, the row and column conductors typically being orthogonally related with the crossing points of the conductors in such matrix being addressable by the application of pulse potentials to the respective conductors in the arrays. Moreover, in such systems, a sustainer voltage is typically applied one-half to the row conductors and one-half to the column conductors. An existing method and system of implementing a diode resistor addressing circuitry employs a transistor in series with the sustainer output and a group of addressing diodes. The series transistor is normally biased ON to insure a low impedance between panel electrodes and the sustaining source. See Johnson U.S. Pat. No. 3,513,327, which discloses the advantages of having a low impedance at this point. When addressing, the transistor must be turned OFF in order for the selected panel electrode to assume a voltage level different from the sustainer voltage. In other words, a pulse voltage ON is algebraically added to the sustainer voltage at selected time intervals (to turn on the panel, for example). Thus, the panel discharge and charging currents (the panel is a capacitive load) passes through the addressing circuits. The present invention is directed to an alternative way of controlling the operation of such discharge panels in that the circuit panel discharge and charging currents do not pass through the addressable sink circuit.-

The above and other objects, advantages and features. of the invention will become more apparent from the following specification and drawings wherein:

FIGS. 1, la and 1b illustrates a typical gaseous discharge display panel and sustainer and addressing matrix system, including typical square wave sustainer waveforms, and

F1G. 2 is a partial circuit diagram which illustrates the split-sustainer operation according to the invention.

Referring now to FIG. 1 of the drawings, gaseous dis charge display panel which is constructed in accordance with the teachings of Baker, et al., U.S. Pat. No. 3,499,167, is constituted by a pair of plates 11 and 12, respectively, support row conductor array 13 and column conductor array 14, each of which is provided with a dielectric coating, it being understood that other arrangements of conductors and dielectric coatings are permissible within the teachings of this invention. A lead oxide overcoat, as disclosed in Ernsthausen U.S. Pat. No. 3,634,719 may be applied to the units. Finally, the plates are joined in spaced apart relation by a spacer sealer element 15 and the thin chamber, typically of about 4 to 6 mils but under 10 mils thickness is filled with a operating medium, preferably such medium being a gas as disclosed in said U.S. Pat. No. 3,634,719..

Panels constructed as described above are supplied with operating potential timed in the manner disclosed in Johnson and Schmersal U.S. Pat. application No. 699,170, filed Jan. 19, 1968, now U.S. Pat. No. 3,618,071.

As disclosed in said Johnson and Schmersal patent, one-half the sustainer potential is applied to row conductor array 13 and the other half is applied to the column conductor array 14, typical row sustainer being shown in FIG. 1A and typical column sustainer waveform being shown in FIG. 1B. In FIG. 1, the supply tems for the row conductor array 13 is designated row address and sustain circuit 18 and the corresponding supply system for column conductor array 14 is designated column address and sustain circuit 19. In FlG. 1, these are shown as a combined unit because of the split nature of the sustainsource. Referring now to F 1G. 2, a partial circuit schematic diagram of the invention is shown, it being understood that in accordance with the legends and plans of connection and development of the circuit for a full panel array not being shown so as to simplify and avoid complication of this disclosure.

Referring now to FIG. 2, the sustainer system is constituted by transistors Q which is the pull up sustaining source and transistor 0,, which is the pull down sustaining source. The bases of transistors Q and Q are controlled in accordance with control signals from a control and data source 20 shown in FIG. 1. In accordance with the system shown with respect to the row sustainer, the pull up sustaining power level is constituted by a variable direct current voltage supply (not shown) but which is known in the art. Thus, in typical square wave sustainer operation, transistor 0,, On being rendered conductive, raises the voltage at point 21 to the sustaining power level and this voltage is applied through coupling diode 22 to node points 23 of a typical resistor-diode address module or element. Such elements are constituted by a resistor 24 and a diode 25 which, in a quiescent state, do not affect the sustained operation. Thus, when point 21 rises to the sustaining power level, corresponding to point A on the row sustainer voltage curve, the panel electrodes connect to that particular nodal point 23 rise to the voltage'level V, of FIG. 1A to thereby charge the panel capacitance. The panel is discharged or returned to a normal level by turning on transistor Q which is the down sustaining source. This returns the panel electrode to the level at the point labelled B in FIG. 1. Note that in accordance with the invention the down sustain transistor switch O is coupled to the gate diodes 25 by way of a coupling diode 50, so the sustainer generator is split. For erase operations, a pull down transistor switch Q, is provided and controlled to connect panel electrodes to a neutral voltage level for erase or removal of information from the panel. The same functional operation occurs with respect to the column sustainer waveform illustrated in FIG. lb at a displaced time interval so that the sustainer potential seen by the gas is, in effect, the difference between the true sustainer waveforms illustrated. The write and erase potentials are applied to the panel electrodes from a supply 30 via .the resistor-diode multiplex matrix and combined with the sustainer source as illustrated in FIG. 2. Diode 60 serves to connect Q which is normally off during addressing operations, to the appropriate write or erase voltage level. This prevents having to charge the collector capacitance of Q through R24.

The logic inputs to the addressable resistor driver circuits 31 are received from the source of data to be entered to the panel, it being appreciated that there may be a plurality of such resistor driver circuits for selected groups of resistors.

An addressable sink circuit 40 is used to sink current from any of M non-adjacent diode-resistor combinations where M X N is the total number of conductors in the conductor array on the panel. This circuit includes input transformer T transistor switch 0,, and diode 41. The diode 41 is for reducing currents through diodes 22 and 25 in the event that Q and are both on. Thus, as shown the discharge and charging (displacement) currents do not pass through the addressable sink circuit 40.

Transistor O is used, during erase intervals, as the down sustain path instead of transistor Q The invention has several advantages over prior art, including:

1. being normally ,off,, no bias supply is required for the addressable sink circuits (such as Q 2. the addressable sink circuits being normally off, the addressing circuitry is not required to provide power to remove stored charge from an on transistor;

3. the addressable sink circuits being normally off, the leading edge of addressing signals to the various electrodes is not subject to differences in delay and reset time caused by non-uniform transistor storage characteristics;

4. since the addressable sink transistors 0;, do not pass panel discharge current, they may have a reduced current capability, which makes for a lower cost, better performance device;

5. the trailing edge of write and erase address signals in the system illustrated is controlled by turning all addressable sink circuits 40 on" at the desired time. Thus, both leading and trailing edges of write and erase pulses are controlled by turning transistors on and the difficult to control and non-uniform process of turning transistors of does not encumber the process of providing address signals to selected electrodes.

While there has been described and illustrated a preferred embodiment of the invention, it will be appreciated that various modifications thereof, obvious to those skilled in the art, are possible, and it is intended to encompass such obvious modifications in the claims hereof.

What is claimed is:

l. A system for supplying electrical operating voltage to conductor arrays of a gas discharge display panel including (l) discharge condition manipulating voltages, and (2) periodic sustain voltages, a resistor diode matrix means for addressing selected ones of the conductors in at least one of said conductor arrays,

said resistor-diode addressing matrix including a plurality of resistor-diode gate elements with a node point between each resistor-diode element, means connecting each node point to a conductor in said array, a plurality of resistor voltage pulsers, means connecting the opposite end of selected N groups of said resistors to a selected one of said resistor voltage pulsers, a plurality of addressable sink circuits, each addressable sink circuit being connected to the opposite ends, respectively, of a selected group of diodes of said resistor-diode elements, and controlled on entry and removal of information to said panel to sink current from any M non-adjacent diode-resistor elements where M X N equals the total number of conductors on said panel,

means for supplying said periodic sustaining voltage including a direct current sustain power supply, having a pair of output terminals,

an up sustain transistor switch connected between one terminal of said supply and an intermediate point, means coupling said intermediate point to the node point of all said resistor-diode elements,

a down sustain transistor switch means, means coupling said down sustain switch to the sides of said diodes opposite said node point.

2. The invention defined in claim 1 including a further transistor switch means connected to said intermediate point for connecting said intermediate point to a neutral voltage level for erase of information from said panel.

3. The invention defined in claim 1 wherein said means coupling said intemediate point to said node point includes a diode.

4. The invention defined in claim 3 wherein said means coupling said down sustain switch to the sides of said diodes opposite said node points includes a diode.

5. The invention defined in claim 1 wherein said means coupling said down sustain switch to the sides of said diodes opposite said node points is consitituted by a further diode.

6. The invention defined in claim 1 including a further diode connected between said down sustainer switch means the resistor ends of said resistor-diode gate elements opposite the node points. 

1. A system for supplying electrical operating voltage to conductor arrays of a gas discharge display panel including (1) discharge condition manipulating voltages, and (2) periodic sustain voltages, a resistor diode matrix means for addressing selected ones of the conductors in at least one of said conductor arrays, said resistor-diode addressing matrix including a plurality of resistor-diode gate elements with a node point between each resistor-diode element, means connecting each node point to a conductor in said array, a plurality of resistor voltage pulsers, means connecting the opposite end of selected N groups of said resistors to a selected one of said resistor voltage pulsers, a plurality of addressable sink circuits, each addressable sink circuit being connected to the opposite ends, respectively, of a selected group of diodes of said resistordiode elements, and controlled on entry and removal of information to said panel to sink current from any ''''M'''' nonadjacent diode-resistor elements where M X N equals the total number of conductors on said panel, means for supplying said periodic sustaining voltage including a direct current sustain power supply, having a pair of output terminals, an up sustain transistor switch connected between one terminal of said supply and an intermediate point, means coUpling said intermediate point to the node point of all said resistor-diode elements, a down sustain transistor switch means, means coupling said down sustain switch to the sides of said diodes opposite said node point.
 2. The invention defined in claim 1 including a further transistor switch means connected to said intermediate point for connecting said intermediate point to a neutral voltage level for erase of information from said panel.
 3. The invention defined in claim 1 wherein said means coupling said intemediate point to said node point includes a diode.
 4. The invention defined in claim 3 wherein said means coupling said down sustain switch to the sides of said diodes opposite said node points includes a diode.
 5. The invention defined in claim 1 wherein said means coupling said down sustain switch to the sides of said diodes opposite said node points is consitituted by a further diode.
 6. The invention defined in claim 1 including a further diode connected between said down sustainer switch means the resistor ends of said resistor-diode gate elements opposite the node points. 